A heater, an electrostatic chuck and the like using a substrate made of a metal such as a stainless steel and an aluminum alloy have been conventionally used, as a semiconductor producing/examining device including an etching apparatus, a chemical vapor deposition apparatus and the like.
However, such a heater made of a metal has the following problems.
At first, since it is made of a metal, the thickness of the heater plate has to be as thick as about 15 mm. This is because, in the case of a thin metal plate, warp and strain are caused due to thermal expansion attributed to heating, so that a silicon wafer put on the metal plate is damaged or inclined. However, in the case the heater plate is made thick, there are problems that the heater becomes heavy and bulky.
Further, by changing voltage and electric current to be applied to the resistance heating element, the temperature of the face for heating (hereinafter, referred to as a heating face) an object to be heated such as a silicon wafer or the like is changed and there is also a problem that the temperature of the heating plate does not follow quickly the change of the voltage and the electric current to result in difficulty of the temperature control.
Therefore, JP Kokai Hei 4-324276 proposes a ceramic heater using an aluminum nitride, a non-oxide ceramic with a high thermal conduction and strength, as a substrate and obtained by forming a resistance heating element and conductor-filled through holes made of tungsten and welding microbe wires as external terminals to them.
Since such a ceramic heater employs a ceramic substrate with a high mechanical strength at a high temperature, the thickness of the ceramic substrate can be thinned to lessen the thermal capacity and as a result, it is made possible that the temperature of the ceramic substrate quickly follows the change of the voltage and electric current.
Further, with respect to such a ceramic heater, as disclosed in JP Kokai 2000-114355 and Japanese Patent Gazette No. 2783980, a cylindrical ceramic and a disk-like ceramic are bonded through a ceramic bonding layer so as to protect wiring of external terminals and the like from reactive gases and halogen gases to be employed for semiconductor production steps.